Pure toneIn psychoacoustics and signal processing, a pure tone is a sound or a signal with a sinusoidal waveform; that is, a sine wave of any frequency, phase-shift, and amplitude. A pure tone has the property – unique among real-valued wave shapes – that its wave shape is unchanged by linear time-invariant systems; that is, only the phase and amplitude change between such a system's pure-tone input and its output. Sine and cosine waves can be used as basic building blocks of more complex waves.
Node (physics)A node is a point along a standing wave where the wave has minimum amplitude. For instance, in a vibrating guitar string, the ends of the string are nodes. By changing the position of the end node through frets, the guitarist changes the effective length of the vibrating string and thereby the note played. The opposite of a node is an anti-node, a point where the amplitude of the standing wave is at maximum. These occur midway between the nodes.
Sawtooth waveThe sawtooth wave (or saw wave) is a kind of non-sinusoidal waveform. It is so named based on its resemblance to the teeth of a plain-toothed saw with a zero rake angle. A single sawtooth, or an intermittently triggered sawtooth, is called a ramp waveform. The convention is that a sawtooth wave ramps upward and then sharply drops. In a reverse (or inverse) sawtooth wave, the wave ramps downward and then sharply rises. It can also be considered the extreme case of an asymmetric triangle wave.
GuqinThe guqin (AUDzh-gu3qin2.ogggu3qin2; ) is a plucked seven-string Chinese musical instrument. It has been played since ancient times, and has traditionally been favoured by scholars and literati as an instrument of great subtlety and refinement, as highlighted by the quote "a gentleman does not part with his qin or se without good reason," as well as being associated with the ancient Chinese philosopher Confucius. It is sometimes referred to by the Chinese as "the father of Chinese music" or "the instrument of the sages".
3rd bridgeThe 3rd bridge is an extended playing technique used on the electric guitar and other string instruments that allows a musician to produce distinctive timbres and overtones that are unavailable on a conventional string instrument with two bridges (a nut and a saddle). The timbre created with this technique is close to that of gamelan instruments like the bonang and similar Indonesian types of pitched gongs. A third bridge can be devised by inserting a rigid preparation object between the strings and the body or neck of the instrument, effectively dividing the string into distinct vibrating segments.
